In a manufacturing step of a semiconductor device, there has been used a thermal processing apparatus for performing a film deposition process etc. to an object to be processed, e.g., a semiconductor wafer. In the thermal processing apparatus, there are prepared recipes in which process conditions such as process temperatures, process pressures, and gas flow rates are written in accordance with types of a film to be deposited and film thicknesses. By selecting one of these recipes, there is performed a thermal process based on the predetermined process conditions.
Even when a thermal process is performed based on the predetermined process conditions, there is a possibility that a film deposition gas might not be sufficiently activated, because a temperature of the film deposition gas tends to be lowered in an area near to a nozzle from which the film deposition gas is supplied. If the film deposition gas is not sufficiently activated, a film is not properly deposited on a semiconductor wafer, which may impair a film thickness uniformity of the film formed on the semiconductor wafer, for example.
In order to solve this problem, Patent Document 1 proposes a film deposition method and a film deposition apparatus that can improve a film thickness uniformity of a film to be formed on a semiconductor wafer, by preheating a film deposition gas with a preheating apparatus immediately before the film deposition gas is supplied into a processing vessel.
[Patent Document 1] JP2003-209099A
However, even when a thermal process is performed based on predetermined process conditions with the use of such an apparatus, there is a possibility that a film thickness uniformity of a film to be formed on a semiconductor wafer might be impaired depending on an individual difference between apparatuses and a type of a semiconductor wafer to be processed. Thus, an operator of the apparatus regulates temperatures of a heater and a preheating apparatus based on the experience and the sense, so as to achieve a film thickness uniformity of a film to be deposited on a surface of a semiconductor wafer.
Namely, in a film deposition process, it is difficult for an operator, who is inexperienced in a thermal processing apparatus and a thermal process, to achieve a film thickness of a film to be formed on a semiconductor wafer. Thus, there has been required a thermal processing apparatus whose temperature can be easily regulated even by an unskilled operator, so that a film thickness uniformity of a film to be formed on a semiconductor wafer can be achieved.